System and method for utilizing oolitic aragonite as a proppant in hydraulic fracking

ABSTRACT

A system for utilizing oolitic aragonite as a proppant in hydraulic fracking is provided. The system includes a proppant storage tank including a stockpile of the oolitic aragonite. The system further includes a proppant pumping unit operable to pump the oolitic aragonite from the proppant storage tank, through an underground shaft, and into an underground fracture proximate to the underground shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure is a continuation of U.S. patent application Ser. No.17/582,829 filed on Jan. 24, 2022 and claims priority to U.S.Provisional Patent Application No. 63/141,188 filed on Jan. 25, 2021,both of which are hereby incorporated by reference.

INTRODUCTION

The disclosure generally relates to a system and method for utilizingoolitic aragonite as a proppant in hydraulic fracking.

BACKGROUND

Hydraulic fracturing or hydraulic fracking is a method by whichincreased amounts of products such as petroleum may be pumped out of anunderground well. A proppant is a material that is pumped into anunderground well that is used to keep a fracture created in the rockopen.

SUMMARY

A proppant as disclosed herein benefits from high roundness, sphericity,and porosity.

A system for utilizing oolitic aragonite as a proppant in hydraulicfracking is provided. The system includes a proppant storage tankincluding a stockpile of the oolitic aragonite, a nozzle configured todeliver the oolitic aragonite into a fracture within an undergroundmining operation, and a proppant pumping unit operable to pump theoolitic aragonite from the proppant storage tank to the nozzle.

In some embodiments, the nozzle includes an articulable nozzle includingrobotic control features.

In some embodiments, the oolitic aragonite includes particles with athreshold roundness.

In some embodiments, the threshold roundness is 0.9 according toKrumbein Shape Factors as tested per API STD-19C.

In some embodiments, the oolitic aragonite includes particles with athreshold sphericity.

In some embodiments, the threshold sphericity is 0.8 according toKrumbein Shape Factors as tested per API STD-19C.

In some embodiments, the oolitic aragonite includes particles with athreshold porosity.

In some embodiments, the oolitic aragonite includes particles with aparticle size of 30 mesh to 50 mesh.

In some embodiments, the oolitic aragonite includes particles with aparticle size of 40 mesh to 70 mesh.

In some embodiments, the oolitic aragonite includes particles with aparticle size of less than 100 mesh.

According to one alternative embodiment, a method for utilizing ooliticaragonite as a proppant in hydraulic fracking is provided. The methodincludes, within an underground horizontal shaft of an undergroundmining operation, providing a flow of high-pressure water configuredcreating fractures in walls of the underground horizontal shaft andproviding with the flow of the high-pressure water a proppant includingoolitic aragonite, wherein the proppant is provided into the fractures.

In some embodiments, the method further includes ceasing the flow of thehigh-pressure water and harvesting petroleum products from theunderground horizontal shaft.

According to one alternative embodiment, a method for utilizing ooliticaragonite as a proppant in hydraulic fracking includes identifying,within an underground mining operation, a fracture attaching a firstunderground chamber and a second underground chamber, maneuvering anozzle operable to deposit oolitic aragonite within or proximate to thefracture, and pumping a proppant deposit including the oolitic aragonitewithin the fracture.

In some embodiments, the oolitic aragonite includes particles with athreshold roundness.

In some embodiments, the oolitic aragonite includes particles with athreshold sphericity.

In some embodiments, the oolitic aragonite includes particles with athreshold porosity.

In some embodiments, the oolitic aragonite includes particles with aparticle size of 30 mesh to 50 mesh.

In some embodiments, the oolitic aragonite includes particles with aparticle size of 40 mesh to 70 mesh.

In some embodiments, the oolitic aragonite includes particles with aparticle size of 100 mesh or smaller.

The above features and advantages and other features and advantages ofthe present disclosure are readily apparent from the following detaileddescription of the best modes for carrying out the disclosure when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a system enabling use of ooliticaragonite as a proppant in hydraulic fracking, in accordance with thepresent disclosure;

FIG. 2 is a flowchart illustrating a method to utilize oolitic aragoniteas a proppant, in accordance with the present disclosure; and

FIG. 3 is a flowchart illustrating a method to direct oolitic aragoniteas a proppant to an identified fracture, in accordance with the presentdisclosure.

DETAILED DESCRIPTION

A system and method for use of oolitic aragonite as a proppant inhydraulic fracking is provided. Bahamian oolitic sand is comprised ofoolites. Oolites are ovoid or egg-shaped particles that form in agitatedshallow-marine waters in tropical settings where the waters include highamounts of calcium bicarbonate. Carbon dioxide is lost to the atmospherethrough degassing as a result of agitation, through elevatedtemperatures from solar radiation, and the activity of photosyntheticorganisms. The loss of carbon dioxide allows precipitation of concentriclayers of calcium carbonate in the form of microscopic layers ofinterlocking crystals of aragonite on pre-existing skeletal orpelletoidal nuclei. Oolitic aragonite particles formed in this mannerare composed of relatively high purity calcium carbonate with uniquephysical properties as compared to similar materials in the art.

To utilize aragonite as a proppant for hydraulic fracturing, raw ooliticsands are harvested from the ocean in the Bahamas or other similarmarine environments. Processing involves drying and sizing raw sand tosegregate oolitic aragonite particles for desired uses and applications.According to one embodiment, a system and method to use ooliticaragonite as a proppant may utilize segregated oolitic aragonite in oneof three size ranges: 30 to 50 mesh, 40 to 70 mesh, and 100 mesh orsmaller.

According to one embodiment, oolitic aragonite used as a proppant mayinclude a threshold roundness, a threshold sphericity, a thresholdpermeability, and/or a threshold porosity.

Oolitic aragonite includes particles with relatively high roundness andsphericity. Filtering devices may be utilized to segregate particleswith threshold roundness and sphericity. Utilizing oolitic aragoniteparticles with threshold roundness and sphericity provides a thresholdporosity and permeability to permit oil and natural gas to pass throughthe particles.

Roundness and sphericity may be described or define according toKrumbein Shape Factors/as tested per API STD-19C, wherein a highestpossible rating is 0.9. According to one embodiment of the disclosure,oolitic aragonite particles may be segregated, and a portion confirmingto roundness=0.9 and sphericity=0.8 may be utilized according to thedisclosed method.

Porosity describes how many holes or depressions a particle has upon itssurface. A spherical particle with high sphericity and high roundnessmay exhibit high porosity. Non-porous particles may be damaged by ahydraulic crushing effect—as high pressure from a high-pressure liquidpress inwardly on the outer surface of the particle, the particle may bedamaged or crushed.

Oolitic aragonite is highly porous, and this porosity reduces ahydraulic crushing effect of high-pressure liquid. High-pressure liquidmay enter the particle through the porous openings, and pressure exertedupon the outside of the particle may be partially or fully equalized bythe pressure of the liquid on the inside of the particle. High porositynegating effects of hydraulic pressure may be helpful during a processof using high pressure liquid to deposit the proppant within undergroundfractures. The high porosity may additionally resist high liquidpressures after the deposition process existing within the undergroundrock formation.

Additionally, when dried, oolitic aragonite particles may forminterlocking networks of needle-like crystals, which create a highlyporous substrate capable of imbibing chemicals. These chemicals are usedfor anti-scaling and other methods meant to inhibit precipitation ofother minerals on the proppant itself. Other naturally occurringproppants lose crush value in fluid under pressure.

As oolitic particles form, alternating concentric layers of aragoniteform and are coated with a protein form called nacre. These alternatingconcentric layers provide additional strength as the particle increasesin size. This is unique as other naturally occurring proppants decreasein crush value as they increase in size. Use of oolitic aragonite asdescribed herein, wholly as oolitic aragonite or mixed in portion withfrac sand, as a proppant improves operation of the proppant, enablingbetter extraction results from the mine over time. Additionally, use ofoolitic aragonite as a proppant requires fewer chemicals to be used atthe time of fracking, reducing costs and an effect of pumping chemicalsinto the ground.

FIG. 1 schematically illustrates a system enabling use of ooliticaragonite as a proppant in hydraulic fracking. An underground verticalshaft 10 is illustrated connecting to an underground horizontal shaft12. The underground horizontal shaft 12 may be drilled in an exemplaryshale deposit which FIG. 1 defines as being below rock layer boundary16. The shale deposit below the rock layer boundary 16 may include asupply of oil, natural gas, or other resources that may be pumpedthrough the underground horizontal shaft 12 and then through undergroundvertical shaft 10 for use as a consumer/industrial product. Oneunderground horizontal shaft 12 is illustrated connected to theunderground vertical shaft 10. More than one underground horizontalshaft 12 may be connected to the same underground vertical shaft 10.Underground shafts may be deep and may run horizontally for longdistances. The illustrated shafts of FIG. 1 are intended to conveyconcepts of the system and process disclosed herein and are not toscale.

Through hydraulic fracking techniques, fractures 14 may be opened in theshale deposit, enabling natural gas and oil within the shale to flowthrough the fractures 14. The fractures 14 are susceptible to collapseor becoming blocked. A proppant 50 may be provided within the fractures14 to support the fractures 14 and prevent them from becoming blocked.Material used to create the proppant 50 may be selected based uponproperties disclosed herein, such as roundness, sphericity, andporosity. In FIG. 1 , the proppant 50 includes oolitic aragonite. In oneembodiment, hydraulic fracking and providing the proppant 50 to thefractures 14 that are created may be performed as a single operation,with the disclosed oolitic aragonite being pumped into the undergroundhorizontal shaft 12 with high pressure water useful to create thefractures 14 and optionally additionally including chemicals useful topromote the fracking process. Once the fractures 14 are created and theproppant 50 is provided into the fractures 14, the high pressure watermay be deactivated, and the site may be utilized to harvest petroleumproducts.

The system of FIG. 1 enabling use of oolitic aragonite as the proppant50 includes a proppant pumping unit 20 and a proppant storage tank 30providing a supply of oolitic aragonite. The proppant pumping unit 20and the proppant storage tank 30 may be disposed upon an above groundsurface 18. The proppant pumping unit 20 provides pumping pressure and aflow of liquid useful to deliver proppant from the proppant storage tank30, through the underground vertical shaft 10, through the undergroundhorizontal shaft 12, and into the fractures 14. In one embodiment, theproppant pumping unit 20 may utilize a flow of water to carry particlesof the proppant 50 through the system. A number of additional oralternative system components are envisioned, and the disclosure is notintended to be limited to the examples provided herein.

A method for using oolitic aragonite as a proppant in hydraulic frackingis disclosed. The method may include a first step identifying, within anunderground mining operation, at least one fracture requiring a proppantto prevent the fracture from closing. A second step may include pumpinga proppant deposit including the oolitic aragonite within the fracture.

FIG. 2 is a flowchart illustrating a method 100 to utilize ooliticaragonite as a proppant. The method 100 starts at step 102. At step 104,a drill is utilized to create an underground vertical shaft. At thisstage, cement and/or metal piping may be utilized to reinforce sidewalls of the shaft. At step 106, a drill bit used by the drill is turnedto create an underground horizontal shaft. At step 108, high-pressurewater, created by an above ground pump device, and oolitic aragonite arepumped into the horizontal shaft. This high-pressure water fracturesshale or other rock surrounding the horizontal shaft, causing smallfractures or cracks in the rock to form. The oolitic aragonite is forcedinto the cracks with the high-pressure water. At step 110, thehigh-pressure water is deactivated. The oolitic aragonite remains withinthe cracks and acts as a proppant, keeping the cracks upon and allowingpetroleum products to flow past the oolitic aragonite. At step 112, thepetroleum products are pumped out of the shafts. At step 114, the method100 ends. A number of additional or alternative method steps areenvisioned, and the disclosure is not intended to be limited to theexamples provided herein.

Method 100 is a method for providing oolitic aragonite within fracturescreated within a horizontal shaft, with the oolitic aragonite beingprovided generally with a flow of high-pressure water. FIG. 3 is aflowchart illustrating a method 200 to utilize a robotic nozzle toprovide oolitic aragonite as a proppant in an identified undergroundfracture. Method 200 starts at step 202. At step 204, a fracture withinan underground mining operation, such as within an undergroundhorizontal shaft, is identified as being a candidate for use of aproppant. In one example, a fracture may be identified as attaching afirst underground chamber and a second underground chamber, and use of aproppant to prevent the fracture from closing up will be beneficial to amining operation to harvest petroleum products. At step 206, a nozzleoperable to deposit oolitic aragonite within or proximate to thefracture is maneuvered to the identified fracture. At step 208, a pumpis utilized to deliver water and the oolitic aragonite into thefracture. At step 210, the method 200 ends. A number of additional oralternative method steps are envisioned, and the disclosure is notintended to be limited to the examples provided herein.

While the best modes for carrying out the disclosure have been describedin detail, those familiar with the art to which this disclosure relateswill recognize various alternative designs and embodiments forpracticing the disclosure within the scope of the appended claims.

What is claimed is:
 1. A system for utilizing oolitic aragonite as aproppant in hydraulic fracking, comprising: a proppant storage tankincluding a stockpile of the oolitic aragonite; and a proppant pumpingunit operable to pump the oolitic aragonite from the proppant storagetank, through an underground shaft, and into an underground fractureproximate to the underground shaft.
 2. The system of claim 1, whereinthe oolitic aragonite consists of particles with a threshold roundness.3. The system of claim 2, wherein the threshold roundness is 0.9according to Krumbein Shape Factors as tested per API STD-19C.
 4. Thesystem of claim 1, wherein the oolitic aragonite consists of particleswith a threshold sphericity.
 5. The system of claim 4, wherein thethreshold sphericity is 0.8 according to Krumbein Shape Factors astested per API STD-19C.
 6. The system of claim 1, wherein the ooliticaragonite consists of particles with a threshold porosity.
 7. The systemof claim 1, wherein the oolitic aragonite consists of particles with aparticle size of 30 mesh to 50 mesh.
 8. The system of claim 1, whereinthe oolitic aragonite consists of particles with a particle size of 40mesh to 70 mesh.
 9. The system of claim 1, wherein the oolitic aragoniteconsists of particles with a particle size of 100 mesh or smaller.
 10. Amethod for utilizing oolitic aragonite as a proppant in hydraulicfracking, comprising: within an underground horizontal shaft of anunderground mining operation: providing a flow of high-pressure waterconfigured creating fractures in walls of the underground horizontalshaft; and providing with the flow of the high-pressure water theproppant including the oolitic aragonite, wherein the proppant isprovided into the fractures.
 11. The method of claim 10, furthercomprising: ceasing the flow of the high-pressure water; and harvestingpetroleum products from the underground horizontal shaft.
 12. A methodfor utilizing oolitic aragonite as a proppant in hydraulic fracking,comprising: identifying, within an underground mining operation, afracture attaching a first underground chamber and a second undergroundchamber; maneuvering a nozzle operable to deposit the oolitic aragonitewithin or proximate to the fracture; and pumping a proppant depositincluding the oolitic aragonite within the fracture.
 13. The method ofclaim 12, wherein the oolitic aragonite consists of particles with athreshold roundness.
 14. The method of claim 12, wherein the ooliticaragonite consists of particles with a threshold sphericity.
 15. Themethod of claim 12, wherein the oolitic aragonite consists of particleswith a threshold porosity.
 16. The method of claim 12, wherein theoolitic aragonite consists of particles with a particle size of 30 meshto 50 mesh.
 17. The method of claim 12, wherein the oolitic aragoniteconsists of particles with a particle size of 40 mesh to 70 mesh. 18.The method of claim 12, wherein the oolitic aragonite consists ofparticles with a particle size of 100 and smaller mesh.